Presently, there does not exist any jet mixer which is designed to specifically utilize acoustic feedback from downstream of a jet nozzle to enhance the mixing of jet air exiting from a jet nozzle. Rather, a variety of mixers/suppressors have been developed to provide enhanced mixing of two different jet or velocity streams. These improved mixers, for example, have reduced the dimension of the high speed flow passage of the ejector resulting in mechanical and performance limitations. Accordingly, the conventional turbulent mixing process has been used to perform the mixing using the smaller high speed flow passage.
Other jet mixer noise suppressors which have been used to provide mixing of two different velocity streams have been constructed of multiple lobed, radially aligned, alternate passages of higher and lower velocity streams for annular or ring-like geometries. Additional mixer noise suppressors have been constructed using parallel alternate passages for rectangular nozzle geometries. Further, mixer noise suppressors have been constructed using single vortex generators which mix fan air with primary exhaust flow across the engine exhaust area. However, these prior art mixer noise suppressors have involved less than optimum flow mixing rates and poor noise reduction due to noise radiation. In addition, the prior art mixer noise suppressors have been complex, bulky and of considerable length resulting in a mixer which is heavier and more expensive to incorporate into a jet engine.
The jet mixer noise suppressor of the present invention is more suitable than the prior art jet mixer noise suppressors since, by using the feedback of acoustic waves received from the down stream side of the nozzle, the jet mixer noise suppressor of the present invention is able to provide excellent mixing of jet streams while being relatively short in length, lighter in weight and less expensive than the prior art jet mixers. In addition, many applications requiring jet mixer noise suppressors require lower noise output from the device than the prior art mixer noise suppressors can provide. Accordingly, the present invention can be used in these types of applications since the present invention is able to provide greatly enhanced mixing of jet flow streams, thus greatly reducing the noise output from the jet engine.